Lock with an arcuate latch



United States Patent Office 3,531,956 Patented Get. 6, 1970 3,531,956 LOCK WITH AN ARCUATE LATCH Ermanno DEttorre and Lamberto DEttorre, both of 14 Via della Guardiola, 00186 Rome, Italy Filed June 5, 1968, Ser. No. 734,601 Claims priority, application Italy, June 8, 1967, 37,328/ 67 Int. Cl. E05b 65/08, 65/28 US. Cl. 70--136 8 Claims ABSTRACT OF THE DISCLOSURE by a cam arm which has a hollow curved form. A pair of stops are provided on the latch with a different one of the stops contacting the front plate of the box containing the latch in its open position and its closed position.

It is well-known in the art, for fastening doors in an efficacious way to use a series of more or less com licated locks in which a bolt is actuated as a consequence of turnings of a key. It is also well known in the art that most of these locks present a bolt having a level or rectilinear movement, therefore not being in a position to block sliding doors safely.

It is an object of the present invention to provide a safe lock in which the latch has an arcuate shape, and fits into a suitably shaped counter plate. When placed in the locked position the arcuate latch fits through the upper opening provided in the counter plate and goes out through the lower opening in the counter plate, reentering into the lock box. Therefore any possible, incidental mutual movement of the leaves of the door is prevented, and especially if the latch is used to secure said leaves of sliding doors, furthermore, in the leaves of conventional doors the lock of the present invention prevents in an absolute manner any breaking and entering of the door.

The safe lock with the arcuate latch, according to the present invention, in addition to the annular latch is provided with means for rotating the latch around its fulcrum, turning the key only one time between two positions, namely, a rest and a working position. These and other objects of the present invention will be more apparent from the following detailed description, in connection with the enclosed drawings, given only for illustrative purposes.

The FIG. 1 is a view of the inside of a lock, in accordance with the present invention, with the cover plate removed;

The FIG. 2 is a view and a partial section of an arcuate latch;

The FIGS. 3, 4 and 5 illustrate details of the lock of the FIG. 1;

The FIG. 6 is a detail of the mounting of the lock of the FIG. 1; and

The FIGS. 7 and 8 are details of jigs for positioning the lock on a door.

Referring now to the drawings, the lock with the arcuate latch, in connection with this invention, comprises a box 1, an arcuate latch 2, and elements for controlling and blocking the aforesaid latch.

Namely, the latch 2 is provided with stops 3 and 4 which abut a front plate 5 of the lock in connection with its two positions. The latch is provided with a glyph 6 the purpose which will be explained later. In addition, the latch is constrained to its center of rotation or fulcrum 7 through a cam-arm 8. The cam-arm 8 is suitably bent with a hollow interior shape in which to house the elements of the lock. Provided on the bottom of the box 1 are some rustications or projections on which is running the latch rides, the rustications or projections 9 act as points of support for the latch 2 preventing the latch from contacting the inner surface of the box 1. In relation to a selvage 10 of the lock, and secured to the selvage, is a trilobate element 11, the longer of its three lobes carrying a pin 12 turned toward the inner surface of the box.

The pin fits the glyph 6 of the latch 2 when the lock is operated and tends to drag the glyph with it. The trilobate element 11, the purpose of its other two lobes will be pointed out later, rotates together with the selvage 10, in which is inserted the safe-key, acting during its rotation, on a cam 13 provided under the selvage 10 and under a plate 34, to which is fastened the fixed portion 14 of the lock.'The fixed portion 14 of the lock is assembled on the bottom of the box by the screws 15, which, when the lock is in the rest position, that is when the lock is either open or closed, are covered by the two other shorter lobes of the trilobate element 11.

The cam 13 is inserted therefore, between the projections 16 of two symmetric sliders 17, 17, each of which has an'appendage 18 able to engage in suitable cavities 19 of the latch 2. In the rest position of the lock, that is when the lock is either closed or open, the appendages 18 of the sliders 17, 17' are housed in the 1 cavities 19 of the latch preventing its movement. When,

after inserting the key in the selvage 10, the rotation of the key begins and as a consequence the rotation of the element 11, and of the cam 13 coupled with it takes place therefore, the two sliders 17, 17 are moved horizontally, before the pin 12 is engaged within the glyph 6, and the gliders move along their axis determined by the buttonholes 20, which slide on the pins 30 supported by the box 1, thereby releasing the respective appendages 18 from the cavities 19 of the latch. Keeping up the actuation of the key, the selvage 10 rotates and with it rotates the complex made up of the trilobate body 11 and of the cam 13, therefore, as a consequence of the engagement of the pin 12 in the. glyph 6, the latch 2 rotates about its fulcrum 7 by means of the carnarm 8. Consequently the latch 2 covers an arc of circle of 180 and after this movement the latch is in a position opposed to the former one, i.e. it is either entirely positioned in the box 1 or fully engaged in the counter plate 21.

In this second arrangement, i.e. in the arrangement of the operation of the closing the door, the latch 2 is engaged within the counter plate 21, i.e. the latch enters the counter plate 21 through the hole 22 and then passes through the hole 23 of the counter plate 21 re-entering the box 1, this movement is terminated when the stop 4 rests against the inner surface of the plate 5. In this position the appendages 18 of the sliders 17, 17' are housed in the cavities 19, and, the latch having completed its rotation of 180, the key can be withdrawn from the selvage 10, with the cam 13 interposed between the projections 16 of the sliders 17, 17' in the narrower position.

We must point up that positioned between the holes 22 and 23 in the counter plate 21 there is an arc-shaped strengthening member 24 against which the inner face of the arcuate latch 2 is juxtaposed, and, on the portion directed towards the inner surface of the counter plate 21,

two longitudinal tongues 25 are provided, which constitute strengthening elements of the counter plate in its more stressed point.

In connection With the foregoing description, the importance of a safe lock of the explained construction is apparent and manifest, because once the latch is rotated into the locked position, i.e. when the latch is engaged within the counter plate, it is impossible to separate the two leaves and such separation is possible only by opening the lock or demolishing one of the two leaves of the door.

For the best way of fastening the lock within the door, in addition to the screw in front of the plate 5 and of the counter plate 21, on the box and on the counter plate 21 there are provided threaded holes 26, 27 respectively, into which screws 28 are conveniently fitted which therefore act transverse to the plane of movement of the latch and, as consequence, in the event it is attemped to force the door, the screws must be sheared or in some way removed, which can be attained only be demolishing a leaf of the door.

From an aesthetic point of view, it is important in such a lock that the screws 28 be provided with screwed caps 29, for hiding the screw heads. Also of considerable interest is the possibility of setting these screws 28 in a very simple way. When the lock is installed, using the jigs shown in the FIG. 7 and 8, it is possible to determine accurately the position in which to make the holes 26, 27 without any trial and error. Accordingly, the jig for tracking the holes 26 is shown in the FIG. 7, the jig being a plate with a wing bent at 90, and provided in its larger part is a hole corresponding to the hole for the introduction of the key and with two other holes corresponding to the holes 26 of the box 1. Likewise, the plate in the FIG. 8 gives the possibility of centering the hole 27, as on the part bent at a right angle to and applied to the thickness of the door leaf there are provided bent tongues, which enter the holes 22 and 23 determining in this Way the exact position of the hole 27 for housing the screw 28.

We claim:

1. A lock for securing doors in the closed position, and particularly for securing the individually leaves of sliding doors in the closed position, comprising a box arranged to be fitted into one of a door and the part to which the door is secured in the closed position, a counter plate lined opposite said box in the other one of the door and the part to which the door is secured in the closed position, a front plate in the side of said box facing toward said counter plate, a fixed lock portion positioned within said box, screws arranged for securing said fixed lock portion to said box, a lock selvage positioned within said fixed lock portion and arranged to be rotated by a key inserted in said selvage, a trilobate element secured to and rotatable with said selvage, two of the lobes of said trilobate element being diametrically opposed across said selvage and the third lobe approximately equiangularly spaced from the other two lobes, an arcuate latch positioned within said box, means for rotatably mounting said latch for movement between an opened position with said latch positioned wholly in said box and a closed position with said latch extending from said box into locking engagement with said counter plate, said means for rotatably mounting said latch comprising a cam-arm secured atone end to said latch and rotatably secured at its other end to said box, a pair of stops attached to said latch and with one of said stops acting as an arresting member for the latch and arranged to contact said front plate within said box when said latch is in the opened position and the other of said stops acting as an arresting member for said latch and arranged to contact said front plate within said box when said latch is in the closed position, said latch having a slot formed therein, a pin secured to one of said lobes of said trilobate member for engaging the slot in said latch for moving said latch between its opened and closed positions, and the other two of said lobes arranged to cover said screws securing said fixed lock portion to said box when said latch is in the open position and in the closed position.

2. A lock, as set forth in claim 1, wherein said latch forming a part of a circle, said stops being spaced from one another on the latch and being located adjacent one end of said latch, and each of said stops having a surface projecting inwardly from the inner periphery of said latch for contacting the inner surface of said front plate.

3. A lock, as set forth in claim 2, wherein said camarm comprises a first end part secured to said latch and extending inwardly from the inner periphery of said latch, said first end part having a radially extending slot opening to the interior of said latch, and said first end part being located between said stops.

4. A lock, as set forth in claim 1, wherein a cam is secured to and is rotatable with said selvage, a pair of symmetrically arranged sliders mounted in said box and displaceable in a linear direction, a projection on each of said sliders being engageable on an opposite side of said cam secured to said selvage, and an appendage secured to and extending from at least one end of each of said sliders and said latch having cavities formed in its inner periphery for engagement by said appendages for securing said latch in the open and the closed positions.

5. A lock, as set forth in claim 1, wherein said counter plate comprises a plate member extending chordally relative to the rotational path of said latch, said plate member having a pair of spaced openings therethrough so that as said latch is rotated into the closed position, it passes first through one of said openings and then through the other thereof for completing the'locked engagement, and stiffening means being provided on said plate member between the openings therethrough and along the sides of said plate member adjacent the open- 1I1gS.

6. A lock, as set forth in claim 1, wherein said box having a plurality of projections formed thereon extending inwardly toward said latch and being arranged in the path of rotation of said latch for supporting said latch out of contact with the interior of said box.

7. A lock, as set forth in claim 1, wherein said box and said counter plate having threaded screw openings therethrough extending perpendicularly to the plane of rotation of said latch, threaded studs arranged to extend through the door and the part to which the door is secured for retaining said box and counter plate in place, and cap screws threadedly engaged in the ends of said studs for covering the ends of said studs exposed in the door and the part to which the door is secured.

8. A look, as set forth in claim 4, wherein pins secured to the inside of said box and extending inwardly therefrom, said sliders having a pair of spaced holes therein arranged to receive said pins, said holes being elongated in the direction of linear movement of said sliders wherebysaid sliders are guided by said pins in their linear movement.

References Cited UNITED STATES PATENTS RICHARD E. MOORE, Primary Examiner E. J. MCCARTHY, Assistant Examiner US. Cl. X.R. -139 

